Funding Information: The development of the online FAIREHR platform was supported by ECETOC (European Centre for Ecotoxicology and Toxicology of Chemicals). Publisher Copyright: © The Author(s) 2025.; The FAIREHR (Findable, Accessible, Interoperable, Reusable Environmental and Health Registry) platform is a state-of-the-art online registry for prospective harmonization of human biomonitoring (HBM). It was devel...